"This series attempts to make LSA more friendly for large (i.e. bigger
than LSA segment) allocations. It is achieved by introducing segment
zones – large, contiguous areas of segments and using them to allocate
segments instead of calling malloc() directly.
Zones can be shrunk when needed to reclaim memory and segments can be
migrated either to reduce number of zone or to defragment one in order
to be able to shrink it. LSA tries to keep all segments at the lower
addresses and reclaims memory starting from the zones in the highest
parts of the address space."